If you just want to do the inserts, a local interior shop would probably be your best bet. If you want to go for whole seat covers, katzkins makes custom fit ones.
I have a group guy going on right now for 590 + shipping, from classicsoftrim.com check out their website, then do alot of the sema vehicles. Check out my post in this formum. Around 7 of us just ordered them for our grand prixs.